A general fire-blocking door lock structure is shown in FIGS. 13 and 14. Such fire-blocking door lock structure comprises a frame member 10 having a push handle 11, which is mounted on the frame member 10 for being pressed down by hand, and a casing 12 connected with a latch body 12d. 
As shown in the drawings that the push handle 11 is screwed and mounted on the bottom inside the frame member 10 and two fixed supports 13 are connected to the frame member 10 on the bottom inside. Two chutes 13a are installed on both sidewalls of fixed supports 13, respectively, for a sliding shaft 13b to be positioned in-between and fixed on the sidewalls of the push handle 11 by a pin 13c. Meanwhile, a spiral spring 13d is penetratingly secured on the front bottom of each said fixed support 13 by a set pin 13e. Under a normal condition, the spiral spring 13d has its one end abutting on the bottom of the sliding shaft 13b with an upward pressure whereon. Therefore, when the door is closed, the pin 13c penetratively set in the sliding shaft 13b enabling the push handle 11 to be urged against on the top of the frame member 10.
The casing 12 is mounted on the front end of the frame member 10 comprising an actuating piece 12a having a driving portion 12b extended to one end and a passive portion 12c extended to the other end. The driving portion 12b has its one end abutting on the inner part of the push handle 11; whereas the passive portion 12c is in contact with a stop portion 12e inside the latch body 12d in the casing 12.
The casing 12 further has a bar link 12f penetratively set inside thereof for latching and unlatching the door lock. The bar link 12f has both of the ends thereof connected with a first latch body 12g and a second latch body 12h, respectively; in addition, has a connecting link 12i set whereon. Two linking pieces 12j are positioned between the connecting link 12i and one end of the actuating piece 12a. When the actuating piece 12a is nudged and swung, the linking pieces 12j are jointly swung; thereby the connecting link 12i can be nudged to move the bar link 12f. The first latch body 12g and the second latch body 12h are positioned inside latch body supports 12k and 12l and pivotally connected to driving pieces 12m and 12n, respectively. The driving pieces 12m and 12n are separately connected to the bar link 12f, thereby enabling the first latch body 12g and the second latch body 12h to be pulled by the bar link 12f. 
The bar link 12f is further linked with a holdfast member 12p, which is positioned inside the frame member 10 away from the casing 12. The holdfast member 12p comprises a clamp 12q with a hook portion and an operating piece 12r. The operating piece 12r is coaxial to and clenched the clamp 12q. The hook portion of the clamp 12q can be pivotally turned corresponding to an axis between a first and a second positions; among which the first position is at the position of the bar link 12f for clenching and opening the door latch; where the second position is at the position of the bar link 12f for unclenching and opening the door latch. A spring 12s is placed at any position of either the first position or the second position biased with the clamp 12q, in addition, an axial extension piece 12t is used for axially holding the operating piece r and the clamp 12q. 
When the push handle 11 positioned on the center of the door inside the frame member 10 is pressed down, the driving portion 12b of the actuating piece 12a is forced to move downwards by the pressure, thereby impelling the passive portion 12c on the other side thereof to move upwards. Meanwhile, the passive portion 12c has the end thereof abutting on the latch body 12d around the stop portion 12e and turning in the counterclockwise direction; thereby the bar link 12f is able to shift the first latch body 12g and the second latch body 12h. Consequently, the latch body 12d can be retracted into a slide support 12o in the casing 12, in addition, the first latch body 12g and the second latch body 12h are forced to shift toward the direction of the latch body 12d, thereby unlatching the door.
In view of the motion of unlatching the said conventional fire-blocking door lock, in spite that a user can perpendicularly press down the push handle 11 by hand, the push handle 11 is moved along the slant direction of chutes 13a on the fixed support 13 inside the frame member 10, that is, the push handle 11a is perpendicularly and horizontally moved along the chutes 13a. Therefore, the physical strength by the user's hand on the push handle 11 is decomposed into a perpendicular force for jointly actuating the latch body 12d and a horizontal force having no effect on the latch body 12d; consequently, the user must exert greater strength on the push handle 11. Moreover, excessive force on the latch body 12d could cause damage to the door latch.
In the meantime, a horizontal force is generated when the push handle 11 is shifted along the chutes 13a, the direction of such a horizontal force is different from that of a force pressed down by a user, so as to cause an uncomfortable feeling of a user and the inconvenience of unlatching and latching the fire-blocking door when the user presses down the push handle. Moreover, the hook portion of the holdfast member 12p pivotally turned corresponding to an axis between the first and the second positions is easily departed from the original position due to a strike or destruction by intention, thereby the efficacy of the operating piece 12r in the latch is failed. The spring 12s placed at either of the first or the second positions then fails to be biased with the clamp 12q without appropriate retaining force, thereby the operating piece r and the clamp 12q can not be properly actuated.
In addition, even though the first latch body 12g and the second latch body 12h can be pulled by the bar link 12f, the latch bodies 12g and 12h and the bar link 12f can merely be driven by the driving pieces 12m and 12n connected to the bar link 12f when the door lock is unlatched. While under the pressure, both of the first latch body 12g and the second latch body 12h are displaced or swung without proper support or actuating mechanism applied, such that the first latch body 12g and the second latch body 12h can not be surely moved toward the direction of the latch body 12d for successfully unlatching the door.
Moreover, as there is no an appropriate restorable force provided by any structure or components among the first latch body 12g, the second latch body 12h and the bar link 12f, therefore, when the opened door is locked up, the first latch body 12g and the second latch body 12h can not be easily restored to the original positions; or the lock of the door latch is easily damaged owing to an external force or improper beats or strikes. Said damages to the door latch not only easily shorten the lifespan of the door latch, but also result in the problem of failing to latch or unlatch the door lock.
The said conventional fire-blocking door lock structure has various problems; for example, the door lock structure requires a greater physical strength to actuate the door latch, and in addition, the lifespan of the door latch is easily shortened and the efficacy of a fire-blocking door usage is reduced without any proper support, actuating mechanisms and restorable force by various door lock components. It is obvious that such a conventional fire-blocking door lock structure requires to be improved.